Woven webbings have long been used as straps and slings for luggage handles, child restraints, animal harnesses, and for securing or supporting various objects. A typical prior art, woven strap is shown in FIG. 1. The woven strap 10 typically is formed by weaving a tube from warp yarns 12, 14 and a weft yarn 16, and then flattening the tube to form a 2-ply woven strap. The two plies 18, 20 are woven together by binder yarns 22. Stuffer yarns 24 typically are sandwiched between the two-plies 18, 20 for increasing the overall strength and/or thickness of the woven strap 10.
When such straps are used as a cargo-securement device such as a cargo tie-down or sling, the edges of the straps often come into contact with sharp objects which can abrade and/or cut the edges, causing the strap to tear or break. U.S. Pat. No. 4,856,837 discloses a two-ply woven cargo sling designed to resist tearing or breaking of the sling. According to the '837 patent, the edges of the sling are strengthened relative to the central region by weaving vinyl-coated yarns along the edges. These strengthened yarns are said to improve the sling by making the edges more resistant to abrasion and cutting. This approach has the drawback of requiring special, strengthened material along the edges of the sling, thereby increasing the cost of manufacturing the sling. It also has the drawback of stiffening the edges of the sling relative to the central region, thereby making the sling less suitable for human or animal contact (if such a sling were to be used in certain contexts other than as slings).
Accordingly, it is an object of the invention to provide an improved strap of woven webbing having edges which effectively resist abrasion and cutting.
It is a particular object of the invention to provide an improved tie-down, load restraint web or sling having cut resistant edges.
Another object of the invention is to provide a strap of woven webbing having soft, flexible edges suitable for contact with a human or animal.
Another object of the invention is to provide a strap of woven webbing that has uniform elongation properties across its cross-section.
Yet another object of the invention is to provide a strap of woven webbing having the foregoing properties which is simple and economical to manufacture.